Kinetic Energy Release and Position of the Transition State for С 6 Н 7 + Ions Produced from Isomeric C 7 H 8 O Precursors

The energetic requirement and mechanisms for CHO' loss from the molecular ions of isomeric C 7 H 8 O precursors have been reported. The heat of formation of [C 6 H 7 ] + (protonated benzene) was determined and ε* evaluated. Measurement of the kinetic energy release T B gives the energy-partitioning quotients q= TB/ε r * which range from 0.38 to 0.99. The energy available and T B are small for the strongly endothermic reaction of benzyl alcohol but increase sharply in the case of the weakly endothermic reaction of anisole. All reactions have "late" transition states, the position X 0 *of the transition state on the reaction coordinate varying from 0.64 to 0.93